Screen‐printed Electrode Modified with ZnFe2O4 Nanoparticles for Detection of Acetylcholine

In this paper a sensor to detect acetylcholine on the basis of ZnFe₂O₄ nanoparticles modified screen printed electrode (SPE) is reported. In the range 0.08–500.0 μM, with the detection limit of 0.024±0.001 μM, acquired anodic peak currents where shown to be linearly dependent on acetylcholine concentrations by differential pulse voltammetry (DPV). It was proven that acetylcholine oxidation at adjusted electrode surface takes place at 100 mV potential less positive compared to an unadjusted screen printed electrode. The electron transfer coefficient (α=0.51) and diffusion coefficient (D=9.3×10^?6 cm²/s) of acetylcholine oxidation were determined too. In addition, this original sensor possesses numerous benefits such as reproducibility, high stability and rapid response (20 s).     

Synthesis,crystal structure,spectroscopic investigations,and computational studies of Ni(II) and Pd(II) complexes with asymmetric tetradentate NOON Schiff base ligand

Structural Chemistry - In the present study, an asymmetric tetradentate NOON Schiff base ligand 2,2′-((4-methyl-1,2-phenylene)bis(nitrilomethylylidene))bis(4-chlorophenol) (H2L) was...     

Salt‐assisted liquid–liquid extraction in microchannel

In this study, for the first time, salt‐assisted liquid–liquid extraction was performed in a microchannel system. The proposed design is based on the increase of contact surface area between target analytes and extracting phase during the sample and extracting phase transfer in microchannel. In this method, first sample solution, extracting solvent, and salt were mixed by stirrer and simultaneously delivered into a microchannel using a syringe pump. In order to optimize the influential parameters on the extraction efficiency of the proposed method, zidovudine and tenofovir disoproxil fumarate were selected as model analytes. The main parameters such as extracting solvent and its volume, salt amount, pH of sample solution, and microchannel shape, length, and its inner diameter were investigated and optimized. Under the optimized conditions, the proposed method was linear in the range of 0.1–30 µg/mL and R² coefficients were equal to 0.9922 and 0.9947 for zidovudine and tenofovir disoproxil fumarate, respectively. Extraction efficiency of the proposed method was compared with conventional salt‐assisted liquid–liquid extraction. The results show that the proposed design has higher extraction efficiency than conventional salt‐assisted liquid–liquid extraction. Finally, the proposed method was successfully applied for the determination of zidovudine and tenofovir disoproxil fumarate in plasma samples.     

Gas mixture effects on ion‐beam flux characteristics from dense plasma focus device: Investigation by the Vlasov–Maxwell equations and experiments

The Vlasov–Maxwell equations were numerically solved to calculate the ion‐beam flux from the plasma of argon and the plasma of mixtures of argon and neon. Some experiments were performed to measure the ion beam from the Amirkabir plasma focus (APF) device. The calculations have shown that the argon ion‐beam flux peaked up to 1.928 × 10³⁰ ions m^?2 s^?1 at the optimum pressure of 1.866 mbar while the neon‐argon mixture's ion‐beam flux reached a maximum of 4.301 × 10³⁰ ions m^?2 s^?1 for 15% neon admixture at the optimum pressure of 1.866 mbar. The calculated kinetic energy of the ion beam has shown a maximum value of 708.7 J for the mixture of 85% argon‐15% neon at the mentioned optimum pressure.     

Investigation of relativistic bosons in the presence of two-dimensional time-dependent harmonic interaction

The Duffin–Kemmer–Petiau (DKP) equation has been exactly solved for the spin-one particle in the presence of time-dependent harmonic potential in a two dimensional space using the Lewis–Riesenfeld dynamical invariant and unitary transform methods. The dynamical invariant has been constructed and its eigen functions have been obtained. The total wave function as well as the evolution operator have been derived.     

New ternary superconducting compound La Ru_2As_2:Physical properties from density functional theory calculations

In this paper, we perform the density functional theory(DFT)-based calculations by the first-principles pseudopotential method to investigate the physical properties of the newly discovered superconductor LaRu_2As_2 for the first time.The optimized structural parameters are in good agreement with the experimental results. The calculated independent elastic constants ensure the mechanical stability of the compound. The calculated Cauchy pressure, Pugh's ratio as well as Poisson's ratio indicate that LaRu_2As_2 should behave as a ductile material. Due to low Debye temperature, LaRu_2As_2 may be used as a thermal barrier coating(TBC) material. The new compound should exhibit metallic nature as its valence bands overlap considerably with the conduction bands. LaRu_2As_2 is expected to be a soft material and easily machinable because of its low hardness value of 6.8 GPa. The multi-band nature is observed in the calculated Fermi surface. A highly anisotropic combination of ionic, covalent and metallic interactions is expected to be in accordance with charge density calculation.     

Fluorescence and Nonlinear Optical Properties of Alizarin Red S in Solvents and Droplet

The enhancement of the nonlinear properties of materials is an interesting topic since it has many applications in optical devices and medicines. The Z-scan technique was used to study the values of the two-photon absorption (β), second-order molecular hyperpolarizability (γ_R), third-order susceptibility (χ_R), and nonlinear refractive index (n₂) of Alizarin Red S in different media using a continuous-wave diode-pump laser radiation at 532 nm. For Alizarin Red S in a droplet, the β, n₂, χ_R, and γ_R were estimated at the order of 10^?7 cm²/W and 10^?12 cm/W, 10^?3 m³ W^?1 s^?1 and 10^?24 m⁶ W^?1 s^?1, respectively. The results indicated that the values of β and n₂ reduced, whereas the values of χ_R and γ_R were enhanced when the solvent was changed from droplet to water, DMF, and dimethyl sulfoxide due to the change in the solvent’s dielectric constant (ε). Moreover, the values of β were enhanced by an increase in the concentration of the surfactant in the aqueous solution. The absorption spectra of Alizarin Red S in the aqueous solution was observed at 428 nm, and a few red shifts in the absorption spectra were observed with a reduction in the dielectric constant of the medium. The same effect was observed in the absorption spectra of Alizarin Red S in the droplet when the bulk dielectric constant reduced. The dielectric constant can affect the fluorescence spectra of Alizarin Red S when the solution is changed from water to dimethyl sulfoxide. The dipole moments of Alizarin Red S in the different media were studied using the quantum perturbation theory.     

The unified method for conformable time fractional Schro¨dinger equation with perturbation terms

The present study implements the unified method to the conformable time fractional non linear Schr$\ddot{\text{o}}$dinger equation with perturbation terms. Reduction of the governing equation to a simpler ODE by compatible complex transform is the first step of the procedure. The predicted solutions in finite series forms of various functions satisfying some particular ODEs are substituted into the reduced form of the governing equation. The algebra is resulted in forming the explicit exact solutions in optical solitary, periodic, elliptic and soliton wave forms represented in polynomial or rational functions.     

A DFT study for adsorption of CO on Ni,Pd and Pt atoms doped (7, 0) boron nitride nanotube

By using density functional theory calculations, we investigated the structural, electronic and magnetic properties of carbon monoxide (CO) adsorption on the pure, Ni, Pd and Pt doped atoms in zigzag single-walled (7, 0) boron nitride nanotubes (BNNTs). The results indicated that compared to the pure (7, 0) BNNTs, replacing B atom by Ni, Pd and Pt atoms can significantly increase the adsorption energy of CO gas on the BNNTs. The adsorption energies of CO gas on the pure (7, 0) Ni, Pd and Pt doped (7, 0) BNNTs are ?0.2013, ?1.746, ?1.593 and ?2.257 eV, respectively. Our results revealed that in comparison with the pure (7, 0) BNNTs, CO gas is chemisorbed on the transition metal doped (7, 0) BNNTs with the appreciable adsorption energy. In addition, it was found that by doping these atoms, band gap energy of the pure (7, 0) BNNTs is considerably decreased. These observations suggested that the Pt doped (7, 0) BNNTs can be introduced as a promising candidate in gas sensor devices for detecting CO gas.     

The Interaction of a New Schiff Base Ligand with Human Serum Albumin: Molecular Docking and Molecular Dynamics Simulation Studies

The interaction of a new heterocyclic Schiff base bearing pyridine and pyrimidine cycles, with human serum albumin (HSA) using molecular docking and molecular dynamics simulation methods was examined. Molecular docking studies showed that the ligand was bonded to the IB domain of the protein. It was found that there was one hydrogen bond interaction between HSA and the ligand. The standard Gibbs free energy for binding of the ligand to HSA was calculated as ?9.63 kcal.mol^?1. The results of the molecular dynamics simulation showed that the root mean square deviation (RMSD) of the non-liganded HSA and the HSA–ligand complex reached equilibration after 1000 ps. The study of the radius of gyration revealed that there was a conformational change when the HSA–ligand complex was formed. Finally, analyzing the RMS fluctuations (RMSF) suggested that the structure of the ligand binding site remained approximately rigid during the simulation.